The present invention relates to a mode selection circuit for selecting an operating mode of an apparatus having a plurality of operating modes.
FIG. 1 shows a typical configuration of a conventional operating mode selection circuit of an apparatus having a plurality of operating modes, and FIG. 2 is a flow chart for explaining a test operation of the apparatus shown in FIG. 1.
In FIGS. 1 and 2, an operating mode selection signal MODESEL for determining an operating mode of an apparatus 100 is generated by setting with a mode switch 1 and directly input to the apparatus 100. When a power switch 2 is turned on or a reset switch 3 is pressed, a reset signal generator 4 generates and supplies a reset signal RESET to the apparatus 100. As a result, the apparatus 100 is operated in an operating mode represented by the operating mode selection signal MODESEL (FIG. 2, step 21). Then, the apparatus 100 is tested (step 22). A result of the test is checked in step 23. If NO in step 23, the flow advances to step 24 to repair the apparatus and returns to step 21 after repair. If YES in step 23, the flow advances to step 25 to check whether the test of all modes has been completed. If NO in step 25, the flow advances to step 26 to set the mode switch 1 to the next mode and press the reset switch 3.
As described above, in order to test all the modes of the apparatus, the mode switch 1 and the reset switch 3 must be manually set and pressed, respectively, before the test of each mode, resulting in a troublesome operation.